Automatic strapping or binding machines, comprising a looping frame and a roller conveyor, are of course known and used for discharging a strapping band or binding strap and for securing the band or strap about packaged articles, boxes, containers, or the like, or a plurality of stacked articles, by means of one or more tensioned binding strap loops. An example of such an apparatus or machine is disclosed within German Patent Publication DE-OS 31 40 577.
In accordance with such conventional strapping or binding techniques, the strapping band or binding strap is initially unwound from a coiled stock of such band or strap, and during a strapping or binding operation, a leading end of the band or strap is inserted into the looping frame of the apparatus or machine by means of the roller conveyor, after a portion of the binding strap or strapping band has encircled the packaged article or stacked articles, so as to be united with or secured to a downstream portion of the band or strap unwound from the coiled stock whereby a strapping or binding loop is formed about or around the packaged article or stack of articles to be bound. Upon proper tensioning of the binding strap or strapping band, the leading end of the binding strap or strapping band is in fact secured to or fixedly united with the downstream portion of the strapping band or binding strap whereupon the downstream portion of the band or strap is severed from the residual coiled stock of the binding strap or strapping band so as to complete the binding of the packaged article or stack of articles. The process is then repeated with respect to additional packaged articles or stacks of articles.
The foregoing automation techniques demand that the binding or strapping process proceeds in accordance with the noted sequence of process steps in a manner or mode which is effectively free from irregularities, jammings, slowdowns, down periods, or the like, so as to in fact achieve a high cycle rate of production. In practice, however, such irregularities or other operational defects do in fact frequently occur because, for example, the leading end of the strapping band or binding strap often becomes jammed within the looping frame. Investigations conducted in connection with such automation apparatus or machinery have demonstrated or revealed the fact that such irregularities or operational breakdowns are caused by means of the looping frame itself. In particular, the roller conveyor represents or serves as a rolling mill which imparts a predetermined percentage reduction to or upon the strapping band or binding strap as the same passes through the roller conveyor, however, the aforenoted percentage reduction imposed upon the binding strap or strapping band is non-uniform because of tolerance characteristics. These results are especially true if the roller conveyor comprises corrugated rolls in order to avoid undesired slippage. As a result of the varying percentage reductions achieved by means of the roller conveyor rolls in connection with or upon opposite longitudinally edges of the strapping band or binding strap, the latter is rolled with a resulting camber effect, with the camber radius disposed within the plane of the drawn strapping band or binding strap.
As can therefore be readily appreciated, the aforenoted camber effect causes the leading end of the strapping band or binding strap to collide with or encounter the interior walls of the looping frame guide devices as the leading end of the strap or band is inserted or introduced into the looping frame. As a result of such collisions or encounters between the leading end of the binding strap or strapping band and the looping frame guide devices, the foregoing irregularities, jammings, or the like, occur whereby the binding or strapping apparatus or machinery is necessarily shut down, slowed down, operated in a reverse manner in order to attempt to alleviate the jammed leading end of the binding strap or strapping band, or the like, all of which in fact militates against or in fact results in the achievement of a substantially low cycle rate of production.